Method and apparatus for managing communications

• US 20060067354A1
• Filed: 09/28/2004
• Published: 03/30/2006
• Est. Priority Date: 09/28/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Waltho, Alan E., Sehiffer, Jeffrey
• Granted Patent: US 8,032,086 B2
• Time in Patent Office: Days
• US Class Current: 370/433
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel

Abstract

Controlling a signal transmitted from a device in a vacant channel in a spectrum.

Claims

1. A method comprising:

controlling a signal transmitted from a device on a channel which an associated receiver has determined to be vacant.

2. The method of claim 1 wherein:

controlling a signal transmitted from a device further comprises transmitting a signal from an unlicensed device in a channel in a licensed spectrum; and

further comprising receiving a usable transmitted signal from a licensed device in the licensed spectrum.

3. The method of claim 1, further comprising scanning a VHF or UHF frequency range with the device for usable signals having a power above a minimum power level in a spectrum including the channel.

4. The method of claim 1, further comprising selecting channels in a spectrum including the channel that are vacant having signals below a minimum power level of a usable transmitted signal in the spectrum.

5. The method of claim 1, further comprising determining the vacant channel by analysis at the device of a pilot tone in the vacant channel to determine that the pilot tone is below a minimum power level of a usable transmitted signal in a spectrum including the vacant channel.

6. The method of claim 1 wherein controlling a signal transmitted from a device further comprises controlling a power of the signal transmitted from the device relative to a power of a signal in an adjacent channel.

7. The method of claim 6, further comprising:

measuring a power of a pilot tone of a carrier in each channel adjacent to the vacant channel; and

wherein controlling a signal transmitted from a device further comprises controlling a power of the signal transmitted from the device relative to a power of a lowest power pilot tone in a channel adjacent to the vacant channel.

8. The method of claim 1, further comprising:

sampling signals from channels in a spectrum including the vacant channel with the device;

identifying channels in the spectrum for which the sampled signal is below a minimum power level of a usable transmitted signal in the spectrum;

ranking the identified channels according to channel ranking rules favoring channels with higher and near equal power signals in adjacent channels; and

choosing a ranked channel over which the device is to communicate.

9. The method of claim 8 wherein:

the device comprises a first device; and

further comprising;

sending the ranking of identified channels for the first device to a second device; and

choosing a channel over which the first device and the second device are to communicate comprising;

comparing the ranking of identified channels for the first device with a ranking of channels for the second device; and

choosing a channel that is a highest ranked channel common to both the first device and the second device.

10. The method of claim 1, further comprising:

sampling signals from channels in a spectrum including the vacant channel with the device; and

for each sampled signal;

setting a center frequency of a narrow band filter;

filtering the sampled signal with the narrow band filter;

measuring a power of the filtered signal from the narrow band filter; and

determining if the power of the filtered signal is below a minimum power level of a usable transmitted signal in the spectrum.

11. The method of claim 1, further comprising:

receiving signals from channels in a spectrum including the vacant channel with the device;

analyzing the received signals with a fast Fourier transform algorithm; and

identifying channels in the spectrum for which a power of a received signal in the channel is below a minimum power level of a usable transmitted signal in the spectrum.

12. A method comprising:

transmitting a signal from a device in a vacant channel in a spectrum; and

adjusting a power of the signal transmitted from the device relative to a power of a signal in a channel adjacent to the vacant channel.

13. The method of claim 12, further comprising:

measuring a power of a pilot tone of a carrier in each channel adjacent to the vacant channel; and

wherein adjusting a power of the signal further comprises adjusting the power of the signal transmitted from the device relative to a power of a lowest power pilot tone in a channel adjacent to the vacant channel.

14. The method of claim 12, further comprising identifying vacant channels in the spectrum over which the device may transmit a signal.

15. The method of claim 14 wherein identifying vacant channels further comprises:

receiving signals from channels in the spectrum in the device;

analyzing a received signal at a pilot frequency in each channel in the device; and

identifying vacant channels for which the received signal at the pilot frequency has a power that is below a minimum power level of a usable transmitted signal in the spectrum.

16. The method of claim 15 wherein analyzing further comprises:

sampling the received signals; and

for each sampled signal;

setting a center frequency of a narrow band filter;

filtering the sampled signal with the narrow band filter;

measuring a power of the filtered signal from the narrow band filter; and

storing the power of the filtered signal and the center frequency as data in a memory.

17. The method of claim 16, further comprising:

filtering the received signals with analog upper and lower adjacent channel filters;

for each channel in the spectrum;

setting a frequency synthesizer to coincide with the channel;

selecting one or more pilot frequencies in the channel; and

for each pilot frequency selected;

setting the center frequency of the narrow band filter near the pilot frequency;

filtering the sampled signal with the narrow band filter;

measuring a power of the filtered signal from the narrow band filter;

performing a dynamic range test of an output of the narrow band filter;

adjusting an automatic gain control attenuator in response to the dynamic range test; and

storing the power of the filtered signal and the center frequency as data in a memory.

18. The method of claim 17 wherein selecting one or more pilot frequencies in the channel further comprises:

selecting a first pilot frequency coincident with a nominal frequency of the channel;

selecting a second pilot frequency that is a selected increment less than the nominal frequency; and

selecting a third pilot frequency that is the selected increment greater than the nominal frequency.

19. The method of claim 15 wherein analyzing a received signal further comprises analyzing the received signal at the pilot frequency in each channel with a fast Fourier transform algorithm in the device.

20. The method of claim 15, further comprising ranking channels in the spectrum for which the received signal at the pilot frequency is below the minimum power level according to channel ranking rules, the channel ranking rules favoring channels with higher and near equal power signals in adjacent channels.

21. The method of claim 20 wherein:

the device comprises a first device, and

further comprising;

sending the ranking of channels for the first device to a second device;

comparing the ranking of channels for the first device with a ranking of channels for the second device ranked according to the channel ranking rules;

choosing a ranked channel that is a highest ranked channel that is common to both the first device and the second device; and

transmitting a signal from the first device to the second device over the chosen ranked channel.

22. A machine comprising a machine-accessible medium having associated information, wherein the information, when accessed, results in the machine performing:

identifying vacant channels in a spectrum;

transmitting a signal in a selected one of the vacant channels in the spectrum; and

adjusting a power of the transmitted signal relative to a power of a signal in a channel adjacent to the selected vacant channel.

23. The machine of claim 22 wherein the information, when accessed, results in the machine performing:

measuring a power of a pilot tone of a carrier in each channel adjacent to the selected vacant channel; and

adjusting the power of the transmitted signal relative to a power of a lowest power pilot tone in a channel adjacent to the selected vacant channel.

24. The machine of claim 22 wherein the information, when accessed, results in the machine performing:

analyzing received signals at pilot tones of carriers of channels in the spectrum, the spectrum comprising a licensed spectrum; and

identifying vacant channels for which the received signals at the pilot tones of the carriers each have a power below a minimum power level of a usable transmitted signal in the spectrum.

25. The machine of claim 24 wherein the information, when accessed, results in the machine performing:

sampling the received signals; and

for each sampled signal;

setting a center frequency of a narrow band filter;

filtering the sampled signal with the narrow band filter; and

measuring a power of the filtered signal from the narrow band filter.

26. The machine of claim 24 wherein the information, when accessed, results in the machine performing a fast Fourier transform analysis of the received signals.

27. An apparatus comprising a transmitter to transmit a signal in a vacant channel in a spectrum with a power adjusted relative to a power of a signal in a channel adjacent to the vacant channel.

28. The apparatus of claim 27, further comprising a receiver to identify vacant channels in the spectrum.

29. The apparatus of claim 28 wherein:

the receiver comprises a circuit to measure a power of a pilot tone of a carrier in each channel adjacent to the vacant channel; and

the transmitter comprises a circuit to adjust the power of the transmitted signal relative to a power of a lowest power pilot tone in a channel adjacent to the vacant channel.

30. The apparatus of claim 28 wherein the receiver comprises a circuit to:

analyze received signals at pilot tones of carriers of channels in the spectrum, the spectrum comprising a licensed spectrum; and

identify vacant channels for which the received signals at the pilot tones of the carriers each have a power below a minimum power level of a usable transmitted signal in the spectrum.

31. The apparatus of claim 28 wherein the receiver and the transmitter comprise an antenna, a receiver circuit coupled to the antenna, a transmitter circuit coupled to the antenna, and a processor coupled to the receiver circuit and the transmitter circuit.

32. The apparatus of claim 31 wherein the receiver circuit comprises a digital signal processing circuit.

33. A system comprising:

an isotropic antenna coupled to a first device to receive signals;

a receiver circuit in the first device coupled to the antenna to identify vacant channels in a spectrum; and

a transmitter circuit in the first device coupled to the antenna to transmit a signal in a selected one of the vacant channels with a power adjusted relative to a power of a signal in a channel adjacent to the selected vacant channel.

34. The system of claim 33 wherein:

the receiver circuit comprises a circuit to measure a power of a pilot tone of a carrier in each channel adjacent to the selected vacant channel; and

the transmitter circuit comprises a circuit to adjust the power of the transmitted signal relative to a power of a lowest power pilot tone in a channel adjacent to the selected vacant channel.

35. The system of claim 33 wherein the receiver circuit comprises a circuit to:

filter signals received by the antenna at pilot tones of carriers of channels in the spectrum; and

identify vacant channels for which the filtered signals have a power below a minimum power level of a usable transmitted signal in the spectrum.

36. The system of claim 33, further comprising a processor coupled to the receiver circuit, the transmitter circuit, and a read-only memory device to control the receiver circuit and the transmitter circuit by executing instructions stored in the read-only memory device.

37. The system of claim 33 wherein the receiver circuit comprises:

a receiver processing circuit coupled to the antenna; and

a narrow band filter coupled to the receiver processing circuit.

38. The system of claim 33 wherein the receiver circuit comprises a digital signal processing circuit with an embedded memory circuit.

39. The system of claim 33 wherein the receiver circuit comprises:

a receiver processing circuit coupled to the antenna;

a digital signal processing circuit coupled to the receiver processing circuit to analyze signals received by the antenna with a fast Fourier transform algorithm;

a peak detect circuit coupled to the digital signal processing circuit to detect peaks in the analyzed signals; and

a processor coupled to the peak detect circuit to receive an output from the peak detect circuit.

40. The system of claim 33, further comprising:

a processor coupled to the receiver circuit and the transmitter circuit;

a volatile memory coupled to the processor to receive, store, and present data used by the processor; and

a non-volatile memory coupled to the processor, the non-volatile memory comprising instructions to be executed by the processor.

41. The system of claim 33, further comprising a second device to communicate with the first device over the selected vacant channel.

42. The system of claim 33 wherein the receiver circuit comprises:

analog upper and lower adjacent channel filters;

a frequency synthesizer;

a narrow band filter; and

an automatic gain control attenuator.